1. Field of the Invention
The present invention relates to a data input device for inputting coordinate data for moving or rotating an image on a screen of a computer.
2. Description of the Related Art
FIG. 7 is a plan view showing a conventional data input device using a so-called track ball.
A spherical operating body 1 (hereinafter, referred to as a track ball) is supported to roll in three- dimensional directions and drives an X-encoder 2 and a Y-encoder 3.
The X-encoder 2 includes a roller 2a rotating about an axis extending in a Y-direction and a disc 2b rotating together with the roller 2a. Cutout portions and non-cutout portions are alternately formed to the outer periphery of the disc 2b at a predetermined pitch in a peripheral direction. A photocoupler 2c confronts the outer periphery of the disc 2b. The photocoupler 2c is provided with a light emitting element and a light receiving element disposed in confrontation with each other and the outer periphery of the disc 2b is interposed between the light emitting element and the light receiving element. When the roller 2a and the disc 2b rotate, a pulse output having a frequency in accordance with the rotational speed of the disc 2b can be obtained from the photocoupler 2c.
Likewise, the Y-encoder 3 is composed a roller 3a rotating about an axis extending in an X-direction, a disc 3b rotating together with the roller 3a and a photocoupler 3c confronting the outer periphery of the disc 3b. Cutout portions and non-cutout portions are alternately formed to the outer periphery of the disc 3b at a predetermined pitch In a peripheral direction. A pulse output having a frequency in accordance with the rotational speed of the disc 3b can be obtained from the photocoupler 3c.
An ordinary input operation when the data input device is connected to a computer will be described below.
When the track ball 1 is rolled in the X-direction, the roller 2a and the disc 2b of the X-encoder 2 are rotated and a pulse output is obtained from the photocoupler 2c and converted into coordinate data. When the coordinate data is input to the computer, a cursor, a character and an object are moved on a screen connected to the computer. Otherwise, when the track ball 1 is rolled in the Y-direction, the roller 3a and the disc 3b of the Y-encoder 3 are rotated and the pulse output from the photocoupler 3c is converted into coordinate data and the cursor and the like are moved on the screen in the Y-direction.
When the spherical operating body 1 is rolled in, for example, an .alpha.-direction which has an angle to both an X-axis and a Y-axis, both the roller 2a and the roller 3a are rotated, pulses from both the roller 2a and the 3a are converted into coordinate data and the cursor and the like are moved in the .alpha.-direction on the screen.
Further, it is possible to input rotation mode data as coordinate data by rolling the track ball 1 while depressing a predetermined key on a keyboard.
When a pulse output is obtained from the photocoupler 2c of the X-encoder 2 by rolling the track ball 1 in the X-direction while depressing the key, the pulse output is converted into rotation data on coordinates and input to the computer. As a result, the character and the object displayed on the screen are rotated about the Y-axis (in a .theta. y-direction). Likewise, when the track ball 1 is rolled in the Y-direction while depressing the above key, the character and the like are rotated about the X-axis (in a .theta. x-direction) on the screen.
That is, the character and the like on the screen are rotated in the same direction as the track ball 1. Therefore, when the track ball 1 is rolled in the .alpha.-direction, the character and the like are rotated about an axis orthogonal to the .alpha.-direction.
As described above, the data input device provided with the track ball 1, the X-encoder 2 and the Y-encoder 3 can input the coordinate data of a moving direction, a moving amount and a moving speed in two-dimension on X-Y coordinates. Further, the data input device can input rotation data about the Y-axis and rotation data about the X-axis in a coordinate rotation input mode. However, since the input coordinate data which can be input by the conventional data input device is limited to the data described above, the conventional data input device has a defect that it cannot input the following data.
When rotation data is input on the coordinates, rotation data about a Z-axis orthogonal to the X-axis and Y-axis cannot be input. That is, as described above, data can be input so that a character and the like are rotated on the screen in the same direction as the track ball by rolling the track ball 1 in the X-direction or in the Y-direction in the rotation mode through the predetermined key depressed. However, even if the track ball 1 is rolled in, for example, a .theta.z-direction (a direction about the Z-axis) in FIG. 7, rotation data about the Z-axis cannot be input. That is, rolling of track ball 1 in the .theta.z direction only results in the rotation of the X-encoder 2 and the Y-encoder caused by the component about the Y-axis and the component about the X-axis of the track ball. At the time, the character and the like only tend to rotate about the X-axis and the Y-axis in accordance with the output pulses from the encoders 2 and 3.
(2) In the input device shown in FIG. 7, moving data cannot be input in a Z-axis direction. Thus, it is impossible to input data for moving, the character and an object on the screen in a Z-direction (the inward and outward directions of the screen).
(3) The addition of a Z-encoder which rotates about the Z-axis permits the input of rotation data about the Z-axis and moving data in the Z-direction. However, it is difficult to rotate the Z-encoder by the track ball 1 with a pinpoint accuracy. That is, since the roller 2a of the X-encoder 2 and the roller 3a of the Y-encoder 3 are positioned below the spherical operating body 1, the track ball 1 is pressed in the Z-axis direction when it is rolled with a finger. With this arrangement, the rollers 2a and 3a can be reliably rotated by the track ball 1. However, it is difficult to reliably rotate the encoder whose axial direction is directed in the Z-axis direction by rolling the track ball with the finger.
Further, the provision of the Z-encoder makes it difficult to make the data input device thin because the size of the track ball in a thickness direction (Z-direction) is increased.
(4) As described above, the conventional input device cannot input coordinate data other than coordinate data based on the X-axis by means of the X-encoder and coordinate data other than coordinate data based on the Y-axis by means of the Y-encoder, likewise. Accordingly, the data input device provided with only the X-encoder 2 and the Y-encoder 3 cannot input three-dimensional data, although it can input two-dimensional data based on the X-Y coordinates as shown in FIG. 7.
An object of the present invention for solving the above problems of the conventional data input device is to provide a data input device capable of individually outputting two coordinate data using one encoder.
Another object of the present invention is to provide a data input device capable of inputting coordinate data in a two-dimensional direction and rotation data about respective three-dimensional axes.